SunEnergyXT launches AC-coupled battery for existing PV systems

A photovoltaic system may have been generating electricity for years before its owner decides to add battery storage. To address this market, Chinese company SunEnergyXT has launched an AC-coupled storage system in Germany. The system is installed entirely on the AC side, allowing it to be added without modifying the existing photovoltaic system or replacing the existing inverter, according to the manufacturer.

The SunEnergyXT 500 PRO AC Core comes with hardware for a future direct connection of PV modules. It features four PV inputs, each with 625 W of MPPT power, or three inputs with 800 W each. The inputs are deactivated in the factory software but can be enabled for an additional fee. This allows the system to be expanded without additional hardware or replacing the storage unit.

Each master unit combines a bidirectional inverter with a rated output of 2,400 W, an AC charging capacity of up to 2,400 W, and a 5 kWh lithium iron phosphate (LFP) battery. The storage capacity can be expanded modularly to 30 kWh by adding up to five expansion units.

Up to two additional master units can also be connected. Each adds 5 kWh of storage capacity and 2,400 W of input and output power. In the maximum configuration, the system provides 90 kWh of storage capacity and an output of 7.2 kW per phase. This allows installers to match storage capacity and power output to the existing PV system and the customer’s electricity demand. The modular architecture also allows the system to be expanded as demand increases.

SunEnergyXT specifies a service life of at least 10,000 charge-discharge cycles and offers a 10-year manufacturer’s warranty.

Commissioning is carried out through the SunEnergyXT app. After installation, the storage system can be connected to a compatible smart meter, including the Shelly Pro 3EM, Shelly EM-50, Eco-Tracker IR, Eco-Tracker P1 and bitShake models.

The system then provides access to intelligent energy management functions. According to SunEnergyXT, it can also be integrated into smart home platforms such as Home Assistant and operated locally without relying on the cloud.

For backup power, the system has an integrated emergency power outlet rated at 2,400 W. In UPS mode, the changeover from grid-connected to off-grid operation takes a maximum of 10 ms, while standard mode requires less than two seconds.

The enclosure has an IP65 rating and is suitable for outdoor installation. The system operates at temperatures ranging from -20 C to 55 C and uses passive, fanless cooling.

“Many operators of existing photovoltaic systems want to store the electricity they generate themselves without having to modify their existing installation. That is exactly what we developed the AC Core for,” said Chengyuan Zhai, managing director of SunEnergyXT.